The present invention relates to a diffusion transfer material and in particular to a photosensitive material for silver complex diffusion transfer process.
Theory of silver complex diffusion transfer process (hereinafter referred to as "DTR process") is mentioned in U.S. Pat. No. 2,352,014 and is known.
According to DTR process, imagewise exposed silver halide emulsion layer is brought into close contact with an image receiving layer in the presence of a developing agent and a silver halide solvent. In the exposed portion of silver halide emulsion layer, silver halide is developed to silver (chemical development) and so is no longer dissolved and cannot diffuse In the unexposed portion, silver halide is converted to a soluble silver complex salt, which is transferred to the image receiving layer, where it forms silver image usually in the presence of physical development nuclei.
Advantage of DTR process is that super-high contrast and dot reproducibility comparable to those of commercially available lith film can be obtained by superposing a photosensitive material for diffusion transfer process and an image receiving layer on each other in a DTR processing solution by a simple processor and besides maintenance of processing solution is easier than in lith system.
DTR process is superior in simplicity of processing as mentioned-above, but with progress of use of the processing solution, exhaustion of the processing solution proceeds to cause reduction of density and lowering of contrast of the resulting image.
Recently, it has been demanded that the processing solution for such DTR process has durability and various investigations have been made. These are disclosed, for example, in Japanese Patent Kokai Nos. 60-212760, 60-212761, 61-73949, 61-73950, 61-73951, 61-73952, 61-73953, and 61-73954.
Furthermore, attempt to improve running processing characteristics by improving photosensitive material for diffusion transfer process has also been proposed and, for example, Japanese Patent Kokai No. 61-238055 has proposed a method therefor.
Such DTR process is often used for preparation of block copies for plate making and for proof and especially, when it is used for the former use, image reproducibility is important and attempts to improve image reproducibility has also been made for photosensitive materials for diffusion transfer process.
The inventors have conducted research to improve image reproducibility and running processing characteristics and have found that image reproducibility and running processing characteristics can be improved when total binder amount in photographic layers on the silver halide emulsion coated side of photosensitive material for diffusion transfer process is adjusted to 6.congruent.8 g/m.sup.2 and ratio of amount of solution absorbed in the layers on the emulsion coated side and the total binder amount on the emulsion coated side in case the silver halide emulsion coated side is immersed in a 0.1N aqueous sodium hydroxide solution at 20.degree. C. for 1 minute is adjusted to 3.5:1-5.5:1.